Relay



July 24, 1934.

C. H. LARSON RELAY Original Filed July 11, 1932 Patented July 24, 1934 nanny can n. Larson, Elkhart,.lnd., aaslgnor to The Adlake Company, Elkhart, 1116., a corporation of Illinois Application Jilly 11, 1932, Serial No. 621,877-

'- Renewed November 29, 1933 16 Claims. (01. 200-112) In neutral relays heretofore generally used in direct current railway signal systems, the movable armature carries spring fingers fitted with contacts to be; closed with fixed contacts.

pages ,7-11, American Railway Signalling Principles and Practices, Chapter VI-Direct current relays. Published by The Signal Section, American Railway Association, 30 Vesey Street, New

1 those defects and be more. durable an'd'reliable under all service conditions.

One form.of such relay is illustrated in the accompanying drawing, in which Fig. 1 is a front elevation of the relay and a casing; 7

Fig. 2 is a vertical section taken on the line 2-2 of Fig. 1;, p

Fig. 3 is a vertical section taken on the line 3-3 of Fig. 2; v Fig. 4 is a perspective view of one of the core pieces and its pole piece, and I Fig. 5is'a wiring diagram.

But the specific drawing and the correspondin specific description are used for the/ purpose of illustration anddisclosure only, and are not intended to impose limitations-on the claims.

The base of the relay-is a box-like casting which 1 includes a back 10 having keyhole slots 11 to receive fastenings, a top 12', a bottom 13, and

sides 14, projecting-laterally from the back 10, and having threaded bosses 15 to receive screws 16 for securing a front or cover 17 made of insulating material, such as hard rubber, fiber, phenolic.

. condensation products and the like, preiorated at 18 to receive cylindrical'soft iron cores 19 0! an electromagnet. The inner or left end (Fig. 2) of each core is threaded into a heavy rectangular pole piece 20, .the two of which are arranged in parallel relation,

one above the other, within the casing. Next to each pole piece is a threaded sleeve 21 within the corresponding opening 18 and secured to the core by a pin 22, and each sleeve receives a nut 23, between which and the corresponding pole piece,

30 the front or cover 17 is clamped, as best shown in Fig. 2;

To the right of the sleeve 21 and nut 23 is a cork washer 24, and next to this is a spool 25 of insulating material on which'is wound a solenoid ,5 26, the two solenoids being connected in series (See with opposite poles adjacent, to each other and having their lead-ins 27 made last to binding posts 28 at the. top of the cover. Approximately even with the outer end of the'spool 25 each core has a shoulder 29 beyond which it is threaded to receive a nut 30, by which a soft iron yoke or back strap 31 is secured in place.

Each pole piece has two transverse openings 32,-corresponding openingsbeing in vertical align"- ment, and those in the lower pole piece are fitted with iron sleeves 33, which project above that pole piece towards the other pole piece and determine the width and location of the air gap in the magnet. I

The cores 19 and back strap 31 constitute an external iron path for the magnetic flux, and consequently a strong magnetic field is produced between the pole pieces when the solenoids are energized.

A glass envelope 34 is loosely fitted in each sleeve 33 and has its upper end cushioned within the opening of theupper pole piece by a rubber tube 35'. Lengths of wire 36 in the form of a coil spring frictionally engage the envelope and rest on the upper ends of the tubes 35 for holding the S0 envelope in place. For added security of ad- 'ustment wax is applied, as indicated at 37 and 38.

Each envelope is a cylindrical tube having a seal-off 39 at the top and a thickened base '40 at the bottom in'which conductors 41 and 42' are sealed. The conductor 41 projects a considerable distance into the envelope and is insulated by a sleeve of glass 43 fused to the base 40. The conductors end in electrodes 44 and 45 and the circuit is closed between them by a charge of mercury 46 when its level is raised to the proper height. A hollow cylinder 47 of Swedish iron, or other material having a high magnetic perm'eabilityand low residual magnetism, serves as a displacer toraise the mercury level, as indicated 95 in'Fig. 3, orallow it to descend to the circuit breaking point when the displacer is raised by the attraction of ,the electromagnet. Each end of the displacer has a plurality of small projections 49 to guide it against the walls of the loo envelope without impairing the flow past the displacer. Light springs 50 of non-magnetic material, such as phosphor bronze, are interposed between the ends of the displacer and the ends of the envelope, to protect the latter during hanthey assume when the magnet is deenergized and the displacer has raised the level of the mercury and closed the circuit between the electrodes 44 and 45. In other words, the illustration is a back contact relay in closed circuit position. Upon energizing th'e magnet the displacer 47 will attempt to close the air gap between its upper end and the upper pole piece 20, and will, therefore,

be lifted a suiiicient distance to permit the mercury to descend below the top of the insulating sleeve 43, thereby opening the circuit. a

It will be obvious to those skilled in the art that by having the sleeves 38 project downwardly from the upper pole piece 20 and adjusting the mercury level and the-position of the mercury switches accordingly, the illustration could be converted into a front contact relay. 7

- It will be apparent that the displacer and the mercury are the only moving parts, and that- L they, with the electrodes, are hermetically sealed within ajglass tube in a selected atmosphere, such as helium, hydrogen, and the like, according to the selection of gas fill, and that there is a minimum of chance for deterioration and failure ofthe relay. Of course, mercury switches are not indestructible, and for that reason the arrangement is made for the convenient replacement of defective switches by new ones.

This is easily accomplished by removing the screws 16, breaking the solder joints 56, withdrawing the old switches, inserting the new, soldering the Joints and returning the cover to the casing.

Theillustration is a 500 chin-relay for a 10 V. D. C. circuit. There are 11,850 turns of No.

30' gauge enameled wire in each coil. The cores 19 are in diameter, and the pole pieces are 1 square and 2%! long. Each glass envelope is; P! outside diameter, and each displacer is" s? outside diameter, 1%" inside diameter and 1 long. f I

With these specific directions an exact repro duction can be made, and thoseskilled in the art can readily make variations to. suit conditions,

without departing from the substance of. the

invention. I'claim as my invention-- .1. In a relay, a horizontally disposed electromagnet including elongated pole pieces, one above and parallel tothe other and each having a vertical opening in alignment with the vertical opening in the other, and a mercury switch mounted in the aligned openings including an hermetically sealed envelope, conductors sealed in the envelope and bearing electrodes spaced apart within the envelope, a charge of mercury adapted to close or open acircuit across the electrodes, according to its level, and a displacer movable within the envelope to displace the mercury and close the circuit, the displacer including magnetic material whereby it is shifted when the magnet is energized;

2."-In a relay, a" pair of horizontal cores spaced one above the other, a pole piece on each core having an opening in alignment wtih an opening in the other, amercury switch comprising a sealed envelope mounted in-the openings. of the pole pieces, conductors sealedin the envelope and bearing electrodes spaced-apart'within the envelope, a charge of-mercury adapted to close or open a circuit across the electrodes accordingto its level, and a displacer movable, within the envelope to'displace the-mercury and close the circult. the displacer including magnetic :material whereby it is shifted when the magnet is ener- 3. In a relay, a pair of horizontal cores spaced one above the other, a pole piece on each core having an opening in alignment with an opening in the other, a mercury switch comprising a sealed envelope mounted in the openings of the pole pieces, conductors sealed in the envelope and bearing electrodes spaced apart within the envelope, a charge of mercury adapted to'close or open a circuit across the electrodes according to its level, and a displacer movable within the en-- velope to displace the mercury and close thecir cuit, the-displacerincluding magnetic material whereby it is shifted when the magnet is energized, and a metal sleeve surrounding the envelope projecting from one pole piece toward the other.

4. In a relay, an electromagnet comprising parallel cores, one above the other, a relatively large the mercury including magnetic material whereby it is shifted when the magnet is energized.

5. Ina relay, a casing having a removable side,

an electromagnet carried on the exteriorof the removable side and. including pole pieces one above the other within the casing and having openings in vertical alignment, and a mercury switch removably mounted in said openings and y including a mercury displacer adapted to span the gap between the poles when the-magnet is energized. V

6. In a relay, a casing, a pair of solenoids mounted horizontally on the exterior face of one of the casing sides, with opposite poles adjacent to one another, core pieces in the solenoids the."

inner ends of which project into thecasing, a strip of magnetic material connecting the"'outer ends of the core pieces, pole pieces within the casing connected to the inner ends of. the core pieces, said pole pieces being one above the other a mercury switch removably mounted in said openings and including a mercury displacer" and having openings in vertical alignment, and

adapted to span the gap between the poles when the magnet is energized. i

r '7. In a relay, a casing including a side, a solenoid mounted on the outer face of the side, spaced 'pole pieces on the inner face of the side, an iron circuit connecting the pole pieces externally, and

passing through the solenoid, one of the pole pieces being above the other and eachhaving openings invertical alignment, and a mercury switch removably mounted in saidopenings and 3 including a mercury displacer adapted to span the gap between the poles when gized. a

8. In a relay, spaced pole pieces one above, the otherand each having a vertical opening in alignthe magnet is enerment with the vertical opening in the other, a I

pair of solenoids mounted side by side, an iron path for the magnetic flux passing through both of said solenoids and joining said pole pieces,

and an hermetically sealed mercury switch re-- .movably mounted in said openings and including a mercury displacer adapted to span the gap between the poles when the solenoids are energized.

9. In a relay, a casing, pole pieces mounted within the casing and comprising blocks of soft iron, one above the other and each provided with a vertical opening in alignment with the vertical opening in the other, iron connectors joining the pole pieces exteriorly of the casing, a coil mounted on one of the connectors, and a mercury switch mounted in the pole piece openings and including a mercury displacer adapted to span the gap between the poles when the coil is energized.

10. In a relay, an electromagnet including pole pieces, one above the other, and each provided with a vertical opening in alignment with the vertical opening in the other, a mercury switch removably mounted in the openings and comprising a switch envelope, spaced electrodes in the envelope, a quantity of mercury in the envelope adapted to make or break an electrical circuit through the electrodes, according to its level, a displacer movable within the envelope to change the mercury level, said displacer including magnetic material whereby it is shifted in response to the coil, and a coil spring tightly fitted over the switch envelope, and engageable with a fixed part of the relay to hold the switch envelope against vertical movement.

11. In a device of. the class described, a boxlike casing having an open front, 'a cover plate adapted to close the front of the casing, meansfor supporting a coil on the exterior surface of the cover, means for supporting pole pieces on the interior face of the cover plate one above the other and each in magnetic relation to the coil, and a mercury switch vertically disposed between the pole pieces, said switch including a displacer adapted to span the gap between the poles when the coil is energized.

12. In a device of the class described, a boxlike casing, means for supporting a coil on the exterior surface of one of the casing faces, means for supporting pole pieces within the casing one above the other, and each in magnetic relation to the coil, and a mercury switch vertically disposed between the pole pieces, said switch including a displacer adapted to span the gap betweenthepoles whenthecoilisenersized.

13. For use in a relay of the class described, a rectangular block of magnetic material having two parallel apertures and a third at right angles to the other two and tapped, and a cylindrical core having a threaded end screwed into the tapped aperture in the block. a

14. For use in a relay of the class described, a rectangular blockof magnetic material having two parallel apertures and a third at right angles to the other two and tapped, a cylindrical core having a threaded end screwed into the tapped aperture in the block, and'an exteriorly threaded collar telescoped over the core and abutting the block. 7

15. In a relay, an electromagnet including pole pieces one above the other, a mercury switch removably mounted in operative relation to said pole pieces and comprising a switch envelope, spaced electrodes in the envelope, a quantity of mercury in the envelope adapted to makeor break an electrical circuit through the electrodes, according to its level, a displacer movable within the envelope to change the mercury level, said displacer including magnetic material whereby it is shifted in response to the coil, and a coil spring tightly fitted over the switch envelope and engageable with a flxedpart of the relay to hold the switch envelOp against vertical movement.

16. In a relay, an electromagnet including pole pieces one above the other, a mercury switch removably mounted in operative relation to said pole pieces and comprising a switchenvelope, spaced electrodes in the envelope, a quantity of mercury in the envelope adapted to make or break an electrical circuit through the electrodes,

according to its level, a displacer movable within the envelope to change the mercury'level, said displacer including magnetic material whereby 118 it is shifted in response to the coil; and means telescoped over the envelope for frictionally holding the switch against vertical movement.

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